Characterizing the X-ray Properties of Clusters of Galaxies
2007 (English)Doctoral thesis, comprehensive summary (Other academic)
Clusters of galaxies are the most massive bound structures known and represent a fair sample of the baryonic and dark matter content of the universe. The hot baryonic gas present in cluster dark matter halos cause them to emit in the X-ray band.
The observed number density of clusters with a given mass is a direct implication of the initial power spectrum of density fluctuations in the early universe and the cosmological parameters. Since mass cannot be directly observed, measurements of the cluster mass function depend on mass-observable relations such as the mass-temperature and luminosity-temperature relations. The understanding of these relations and the underlying physical processes are crucial for using clusters as cosmological probes.
Detailed mapping of cluster properties can be obtained from spatially resolved X-ray spectra from satellites XMM-Newton and Chandra. This work represents an attempt to model these data in the most efficient way, taking into account the associated imperfections of current X-ray mirrors and detectors.
The method of Smoothed Particle Inference (SPI) is developed and applied to a large sample of clusters observed with XMM-Newton. The output of this modeling is used to categorize the clusters, quantify substructure and measure the luminosity-temperature relation separately for multiple subsamples. The normalization of this relation is found to exhibit weak evolution with redshift consistent with some models of cluster formation.
Finally, a new method is introduced, based on the temperature structure of clusters, to distinguish between isothermal clusters, cool core clusters and clusters with a large degree of substructure indicative of a current or recent merger event. This will provide a tool for comparison to simulations of structure formation to test the frequency of merging activity and the efficiency of transport processes in the intra cluster medium.
Place, publisher, year, edition, pages
Stockholm: Fysikum , 2007. , 135 p.
Research subject Physics
IdentifiersURN: urn:nbn:se:su:diva-7001ISBN: 978-91-7155-488-8OAI: oai:DiVA.org:su-7001DiVA: diva2:197456
2007-09-17, sal FB53, AlbaNova universitetscentrum, Roslagstullsbacken 21, Stockholm, 10:15
Fabian, Andrew, Prof.
Goobar, Ariel, Prof.